POLYMERASE-CHAIN-REACTION IN THE DIAGNOSIS OF BACTERIAL ENDOPHTHALMITIS

Background-Microbiological investigations of vitreous fluid (VF) and a queous humour (AH) specimens have often failed to detect the infecting agent in infectious endophthalmitis, resulting in a clinical dilemma regarding therapy. In this study, the polymerase chain reaction (PCR) was evaluated in the diagnosis of bacterial and Propionibacterium acne s endophthalmitis. Methods-58 intraocular specimens (30 VF and 28 AH) from 55 cases of endophthalmitis and 20 specimens (14 VF and 6 AH) as controls from non-infective disorders were processed for microbiologic al investigations. Nested PCR directed at the 16S rDNA using universal primers for eubacterial genome was done. PCR for P acnes was performe d on specimens microbiologically negative by conventional techniques b ut eubacterial genome positive. Results-Of the 20 controls from noninf ective cases, one (5%) was positive using eubacterial primers and none with P acnes primers. PCR for eubacterial genome showed 100% correlat ion with 20 (34.5%) bacteriologically positive specimens. Eubacterial genome, was detected in 17 (44.7%) of 38 bacteriologically negative sp ecimens and nine (52.9%) out of the 17 were positive for P acnes genom e. Among the 21 eubacterial PCR negative specimens, seven were fungus positive. By inclusion of PCR, microbiologically positive specimens in creased from 46.5% to 75.8%. PCR on AH was as sensitive as that on VF for the detection of both eubacterial and the P acnes genome. Conclusi on-PCR performed on AH and VF is a reliable tool for the diagnosis of bacterial and P acnes endophthalmitis particularly in smear and cultur e negative specimens.